1). Field of the Invention
The field of the invention relates to methods and apparatuses for determining fallopian tube occlusion.
2). Discussion of Related Art
Female sterilization prevents pregnancy by occluding or mechanically blocking the fallopian tubes. There are several different occlusion techniques—tubes can be tied or “ligated,” blocked with mechanical devices such as clips or rings, or scarred closed with electric current.
In partial salpingectomy, the fallopian tubes are cut and tied with suture material. The Pomeroy technique, a widely used version of partial salpingectomy, involves tying a small loop of the tube and cutting off the top segment of the loop.
Clips are used to block the fallopian tubes by clamping down and cutting off the blood supply to a portion of the tubes, causing a small amount of scarring or fibrosis that prevents fertilization from occurring. The two most common clips are the Filshie clip, made of titanium, and the Wolf clip (also known as the Hulka clip), made of plastic. Clips are simple to use, but each type requires a special applicator.
Tubal rings, like clips, also block the tubes mechanically. A very small loop of the fallopian tube is pulled through the stretched ring. When the ring is released, it stops the blood supply to that small loop. The resulting scarring blocks passage of the sperm or egg. The Yoon Ring, made of silicone, is widely used.
Electrocoagulation uses electric current to coagulate or burn a small portion of each fallopian tube. Unipolar coagulation passes current through the forceps applied on the tubes, and the current leaves a woman's body through an electrode placed under her thigh. In bipolar coagulation, current enters and leaves a woman through two ends of the forceps.
Occlusion device applied transcervically such as the ESSURE® device manufactured by CONCEPTUS, INC. are also used to permanently block the fallopian tubes.
Hysterosalpingography (HSG) is a known method for determining whether a fallopian tube has been successfully occluded. In HSG, the uterus is pressurized with a fluoroscopically visual fluid. A radiologist fluoroscopically monitors the fallopian tubes to see if the fluid escapes past the occluded portion. Fluid seen escaping and filling the fallopian tubes, for example near the ovaries would indicate that the fallopian tubes are not occluded and that the patient may still be fertile. HSG is problematic in that it requires a radiologist to be present and also requires the use of specialized equipment. Thus HSG also cannot be performed in a doctor's office.